Concrete gun



subjectedto the conveying action of air un Patented Apr. 8, 1924.

UNITED STATES WADE F. WEBB, OF KERNVILLE, CALIFORNIA.

CONCRETE GUN.

Application flied November 17, 1920. Serial No. 424,748.

To all whom it may concern:

Be it known that I, WADE F. Wane, a; citizen of the United States, residing at Kernville, in the county of Kern and State of California, have invented new and useful Improvements in Concrete Guns, of which the following is a specification.

This invention relates to a concrete gun and particularly pertains to an air operated mechanism for conveying plastic mass through a conduit as set forth in a companion application which has resulted in United States Letters Patent No.' 1,362,767, issued to me December 21, 1920.

It is the object of this invention to provide effective means whereby concrete may be forced through a conduit by the direct action of air thereon, and embodying, a mechanism for positively feeding a charge of concrete to the conduit while it is being der pressure. Another object is to provide a concrete gun embodying'a receiving chamber having a piston therein adapted to advance the concrete delivered to the chamber toward a discharge nozzle, and also to provide a means for reciprocating said piston by air under pressure.

Another object is to rovidea novel piston construction which wil l permit of the ready adjustment or removal and replacement of packing elements on the piston to compensate for the unusual wear to which packing rings in pistons employed for this purpose would be subjected.

Another object is to provide a construction and arrangement of parts in a concrete gun whereby it. may be readily assembled and dismantled.

A further object is to provide means for removing concrete from the inner walls of the receiving chamber so as to reduce wear of the piston and chamber walls.

Other objects will appear hereinafter. The invention is illustrated in the accompanying drawings, in which:

.Figure 1 is aview of theconcrete gun asseen in vertical section, partly in elevation.

Figure 2 1s a detail view 1n vertical section showing the construction of the concreteadvancing piston and illustrating the-construction of the piston rings. 'Figure 3 is a. detail section illustrating modified construction of the piston.

More specifically, 5 indicates a concrete receiving chamber which is here shown as comprising a cylindrical casing 6 which may be formed of a section of ordinary steel pipe or an iron casting of suitable dimensions, preferably about 2 feet in diameter. The casing is formed with an inlet opening 7 in the upper portion and adjacent to one end thereof, fitted with a feed hopper 8, and formed on the casing are end flanges 9 and 10 which may be either screwed or cast thereon. The end of the casing remote from the opening 7 connects with an eccentric reducer 11', the bottom wall of which is continued flush with that of the chambeit and the side and top walls of which taperto an outlet 12 connecting with a conduit 13 lead ing to any suitable point of discharge, the bottom wall of which conduit extends on'a plane with the bottom ofthe chamber-5.

.The reducer 11 is preferably detachably connected to the casing by means of bolts 1 which the casing and cylinder are connected together. The partition plate 17 is formed with a central opening through which a piston stem 19 extends; packing rings 20 en;

circling the margin of the opening in the partition plate to form a practically air tight joint.

The piston stem 19 is preferably tubular and formed of pipe externally threaded at its ends to receive flange rings 21 and 22; the

flange ring 21 carrying a piston 23 positioned in the casing and the flange ring 22 carrying a piston 24 disposed in the cylinder 15'. The pistons embody packing rings 25 which shown in Figures 2 and 3, in which the pistons are illustrated as embodying back plates 26 secured to the flange rings 21 or may be readily adjusted, removed, and replaced; suitable forms of the pistons being 22, and a demountable front plate 27 formed with an inwardly projecting annular flange 28 spaced from its outer edge. .A series of four packing rings are preferably mounted on the front Dlate as here shown. The front plate carrying the packing rings, is demountably attached to the back plate 26 by means of bolts 30, which are here shown as passing through the front plate 27 and screwed into engagement with the back plate 26, which construction permits of the front plate and packing members being removed from the forward 'piston 23 and replaced through the opening 7 so as not to necessitate disconnection of the casing 6 and cylinder 15 when it is necessary to renew or adjust the packing member on the piston. In the form of the forward piston shown in Fig. 2, the outer face of the front plate 27 .is formed with a series of channels 31 terminating in an inclined wall 32 at the outer edge of the plate and communicatmg at their inner ends with openings 33 leading to the inner side of the plate in communication with the space interiorly of the flange 28 which opens through the plate 26 to the tubular piston stem 19, which is here shown as formed with an air inlet opening 34 adjacent to the piston 24 so as to admit air from the space within the cylinder 15 and effect discharge of a series of air jets from the forward end of the piston 23 adjacent its periphery and against the walls of. the chamber 5. The channels 31 are covered by a face plate 35, which is placed over the front plate 27 and secured thereto by any suitable fastenings; the face plate 35 affording a removable wearing surface and serving as a protection to the front plate 27. Where air is not to be delivered through the piston, the end plate 27 is formed without channels 31 and openings 33 as shown in Fig. 3, which construction is suitable for the rear piston 24.

The pistons 23 and 24 are designed to be reciprocated by air under pressure, which is delivered alternately to the opposite sides of the piston 24 through air inlet pipes 36 and 37 communicating through control valves 38 and 39 of any suitable character with a conduit 40 leading from any desired source of air under pressure.

The valves 38 and 39 are here shown as consisting of ordinary three-way valves adapted to be positioned to either admit air under pressure adjacent to the outer ends of the cylinder 15 on opposite sides of the piston 24 onto exhaust the air therefrom.

The air for conveying concrete through the conduit 13 is admitted to the chamber 5 through a pipe 41 leading into the lower portion of the reducer 11 through a quick opening agitating valve 42, the air being delivered to this point close to the conduit 13 to prevent choking of the tapered reducer 11. The pipe 41 also opens to chamber 5 through a branch 41 on the pressure side of valve 42 and opens to the cylinder at the upper portion of the inner end of the reducer at a point to direct air against the outer face of the piston 23 when the latter is in its for .ing rings are arranged in place on the piston so as to be removed and replaced through the open outer end of the cylinder 15 when the end cap 43 is removed this piston being constructed as shown in Figure 3.

In the operation of the invention, the piston 23 is retracted by admitting air into the chamber within the cylinder 15 through the valve 39, the air being admitted in such volume and pressure as to act on the piston 24 to move the connected pistons rearwardly and at the same time supply suflicient air to position, a charge of concrete is delivered to the chamber 5 through the hopper 8 and opening 7, whereupon the valve 39 is closed to the air supply and opened to exhaust and the valve 38 closed to exhaust and opened to direct air under pressure rearward of the piston 24, so as to impel the latter in a forward direction and cause the piston 23 to advance therewith.

The char e of concrete delivered to the chamber 5 is positively shoved forward by the piston 23 toward the conduit 13, and when the piston 23 has reached a point be-, yond the opening 7, the valves 42 and 42' are opened to admit air into the space within the chamber 5 between the outer end of the piston 23 and the small end of the reducer, which air under pressure will operate to advance the concrete through the conduit and to convey it to any suitable point of dis charge remote from the receiving chamber; the valve 42 being maintained open, while the valve 42 is quickly opened and closed, to deliver intermittent downwardly directed blasts of air into the body of concrete at the small end of the reducer substantially at right angles to the direction of flow of the concrete and thereby effect an agitating action at the entrance to the discharge pipe and thus prevent clogging or formation of a plug of the concrete at this point and insuring its passage into and through the discharge pipe.

The piston 23 is advanced such distance as to'position the major portion of the charge into the reducer, whereupon the valve 38 is closed to the air supply and iii ted to exhaust, and the valve 39 openig to the air supply to retract the pistons, ne valve 4:2 may be left open until the piston 23 reaches the opening 7, whereupon will be closed during the time the succeeding charge is delivered to the receiving chamber and the piston 23 again advanced. A rod leads from the handle of the valve to a point near. the rear end of the gun, so that the attendant standing near the valves 38 and 39 to operate the latter may also conveniently control the air for conveying the concrete.

As a means for preventing too rapid hacliivvard movement of the pistons in event the conduit should become choked, a check valve 51 is provided in the pipe 36 on the pressure side of the valve 38 to cause an air cushion to be formed back of the piston in event the latter moves rearvvardly before the valve 38 is'opened to-exhaust. Any other suitable means may be employed for preventing accidental retraction of the pistons as occasion may require.

The abrasive character of the material beed causes rapid wear of the packing at nber of the forward piston and necessitating occasional adjustment or replacement oi the packing members. By the construction of the piston as before deed, this may be readily effected by re the fr ont plate 27 through the inhave shown and described a specific emliodnnent of my invention, it is manifest that various changes may be made in the details or construction thereof, vvitlr out departing from the spirit and scope of the invention as set forth in appended 'i a claim:

in a concrete gun,'a concrete receiving chamber, a discharge conduit connected thereto, means for admitting air under pressure to said chamber to convey concrete through said conduit, a piston in said chamber "for advancing a charge of concrete into position to be operated on by the air under pressure, and means for directing blasts of air into the charge of concrete at the en trance to the discharge conduit substantially at right angles to the direction of flow of the concrete.

in a concrete gun, a concrete receiving chamber having a. tapered end leading to a discharge opening, an air conduit connecting with the reduced portion of. the tapered end adjacent to the discharge opening, a piston for advancing concrete in said chnm and an a itatiug valve in said air conm bring air under pi ,s-:surc close the discharge opening to prevent cloga oi? the opening, and means for delivering air under pressure at the enlarged portion of the tapered end to cooperate with the piston in effecting advance of the concrete.

3. In a concrete gun, a concrete receiving chamber, a piston for advancing concrete in said chamber, a cylinder, a piston in said cylinder connected to the first named piston, a pair of air conduits connecting to said cylinder on opposite sides of the piston therein, control valves in said conduits for delivering air under pressure to either side of said piston and exhausting it therefrom whereby said piston may be reciprocated,

the conduit, and means for directing air under pressure into the cylinder adjacent the intersection of the cylinder With its reduced end portion to cooperate with the piston in 'eifecting advance of the concrete.

5. In a concrete gun, a concrete-receiving chamber having a tapered end section leading to a discharge opening, a piston for advancing concrete in said chamber and delivering it to said discharge opening, and an air conduit communicating with the re duced end portion of said tapered end section for delivery ofair under pressure adjacent the discharge opening to prevent clogging of the opening.

6. In a concrete gun, a concrete-receiving chamber having a tapered end portion leading to a discharge opening, a piston for advancing concrete in said chamber and delivering it to said discharge opening, an air conduit for delivering air under pressure to the tapered end portion at a point adjacent the discharge opening to prevent clogging of the opening, and a valve in said conduit adapted to be operated to deliver blasts of air through said conduit.

5. in a concrete gun, a horizontally extending cylinder having a tapered end portion leading to a discharge opening, a conduit leading from the discharge opening, a piston for advancing concrete horizontally through said cylinder, and means for delivering air under pressure into the tapered end portion of the cylinder at the entrance to the discharge opening for agitating the concrete as it enters the conduit.

WADE WEBB. 

